Embryology

Question 1

What does the first pharyngeal arch gives rise to?

Answer 1

The maxillary prominence and mandibular prominence (Meckel’s cartilage)

Question 2

The first pharyngeal is associated with what nerve?

Answer 2

The trigeminal nerve

Gives rise to muscles of mastication (muscles to rember are tensor vali palatini and tensor tympani)

Question 3

What pharyngeal arch does the common carotid artery comes from?

Answer 3

Third

Question 4

Which pharyngeal arch gives rise to only the lower body and horn of hyoid bone?

Answer 4

Third

Question 5

The pharyngeal pouches come from what layer ?

Answer 5

Endodermal|inner surface

Question 6

What structure develops primarily into the thyroid gland?

Answer 6

Foramen cecum at the base of the tongue —— for a short time the gland is connected to the tongue via the thyroglossal duct

Question 7

In a patient born with complete first (pharyngeal) arch syndrome what structures will remain unaffected?

Answer 7

Stapes

Question 8

This syndrome occurs because the third and fourth pouches fail to differentiate between the thymus and parathyroid glands which results in the baby being born without a thymus and parathyroid glands——Congenital hypoparathyroidism

Answer 8

Digeorge syndrome

Question 9

Remnants of a cyst occurs in the tongue or anterior part of the neck, usually inferior to hyoid bone.

Most cysts are observed at the age of .

Most a asymptomatic and movable and contains thyroid tissue.

Perforation of the skin may occur which opens in the median plane of the neck and anterior to laryngeal cartilages.

Name thus congenital anomaly ?

Answer 9

Thyroglossal duct cyst and sinus (perforation of skin)

Question 10

Clinical significance of ectopic sites of thyroid glands

Answer 10

Incomplete movement of thyroid gland results in a sublingual thyroid gland that appears high at the neck just inferior to hyoid bone —- usually only thyroid tissue present

Question 11

What are the components of the pharyngeal arches ?

Answer 11

Mesenchymal core —from mesoderm

Ectoderm

Endoderm

Truncus arteriosus

Cartilaginous rod forms skeletal arch

Muscular component

Sensory and motor nerves

Question 12

First pharyngeal pouch forms what?

Answer 12

The tympanic membrane and pharyngotympanic tube

Question 13

Second pharyngeal pouch forms what?

Answer 13

Forms the tonsils crypts

Question 14

Third pharyngeal pouch forms what?

Answer 14

Inferior parathyroid gland and thymus

Question 15

Fourth pharyngeal pouch forms

Answer 15

The superior thyroid gland

Question 16

What is Treacher Collin’s syndrome?

Answer 16

An autosomal dominant disorder characterized by the malar hypolplasia (underdevelopment of zygomatic bones of the face). A first pharyngeal arch syndrome. ——insufficient migration of neural cyst cells

Question 17

What is Pierre Robin syndrome?

Answer 17

A first pharyngeal arch syndrome which is associated with hypoplasia of the mandibular,e, cleft plate, and defects in eyes and ears. Bilateral cleft plate and posterior displacement of the tongue.

Question 18

Match pharyngeal arches with the muscles and cranial nerves they’re grouped with.

First
Second
Third
Fourth
Fifth

Answer 18

First : trigeminal nerve 
Second : Facial nerve
Third: Glossopharyngeal nerve 
Fourth: superior Laryngeal branch of vagus nerve 
Fifth: Recurrent Laryngeal nerve

Question 19

Fourth and six arches forms what cartilages ?

Answer 19

Thyroid and cricoid cartilages

Question 20

Second pharyngeal arch forms what ligaments and bones?

Answer 20

The stapes bone and the stylohyoid ligament and lesser horn of the hyoid bone

Question 21

First pharyngeal arch forms what bones?

Answer 21

Malleus and Incus

Question 22

First pharyngeal arch forms what muscles ?

Answer 22

Muscles of mastication

Question 23

The second pharyngeal arch forms hat muscles ?

Answer 23

The stapedius, stylohyoid,posterior belly of digastric, auricular, muscles of facial expression

Question 24

The third pharyngeal arch forms what muscles ?

Answer 24

Stylopharyngeus muscle

Question 25

The fourth pharyngeal arch forms what muscles ?

Answer 25

Cricothyroid, levator veli palatini and constrictors of pharynx

Question 26

The six pharyngeal arch forms what muscles ?

Answer 26

intrinsic muscles of larynx

Question 27

What is the cause of Anterior cleft lip defects ?

Answer 27

Deficiency of mesnchyme in the maxillary prominence and median palatine process.

Question 28

What causes posterior cleft defects ?

Answer 28

Defective development of the secondary palate and growth distortions of lateral palatine processes that prevent their fusion. Palatine shelves altered.

Question 29

Unilateral cleft lip is when what two structures unite on one side?

Answer 29

Maxillary and medial nasal prominence

Question 30

Bilateral cleft lip is the result of what two structures not uniting?

Answer 30

Maxillary prominence and and medial nasal prominence

Question 31

What congenital disorder is more common in girls than boys and in love only the uvulas —-difficulty with lateral palatine processes.

Answer 31

Cleft palates

Question 32

What bones of the neck are developed endochondral ?

Answer 32

Larynx, inner ear (stapes💕), and hyoid bone